1. Field of the invention
The present invention is directed to a method and apparatus for injection molding a two-piece plastic assembly. More specifically, the present invention is directed to a method and apparatus that utilizes a linearly moving shuttle mold to simultaneously mold and join a plastic assembly.
2. Description of the Related Arts
U.S. Pat. No. 5,413,743, teaches a method of manufacturing a two-piece headlamp assembly using a rotary platen. The rotary platen utilizes at least two die sets (two pair of matched molds) to form a plastic article. A first die set is used to manufacture a transparent lens. A second die set is used to manufacture a reflector that mates with the lens. The lens is injection molded at a first location on the rotary platen. The reflector portion is molded at a second location on the rotary platen at the same time as the lens. The reflector and lens die sets are opened and the die portion containing the lens is mated with the die portion containing the reflector in a third location on the rotary platen. When the lens and reflector are brought together, they form a cavity. A plastic material is injected into this cavity to join the lens and reflector.
The invention described in U.S. Pat. No. 5,413,743 utilizes at a minimum two separate die sets (four dies) requiring movement between their molding position and their joining position. This movement is achieved through a rotary table.
It is desirable to utilize an injection molding apparatus that may injection mold the two plastic components and then join the components using a single die set. It is further desirable that a single injection molding press be used to mold the components and then create a joining bond therebetween. It is also desirable that each cycle of the molding apparatus both mold the components and create a joining bond between a previously molded pair of plastic components.